Very often a discharge will start out as fluid but will progress to mucoid and then purulent. This may be due to a progression of various infectious agents.

A discharge from both nostrils, often accompanied by fever, loss of appetite, eye discharge, drooling, coughing, or sores in the mouth suggests a feline viral respiratory disease. When both nostrils are blocked by swollen membranes, the cat sniffles, breathes noisily, and may breathe through his mouth. Because cats avoid mouth breathing whenever possible, you may see this sign only when the cat exercises. Any cat who is breathing through the mouth should be examined by a veterinarian.

Foreign bodies usually cause a discharge from just one nostril. This discharge can range from bloody to purulent. Allergic rhinitis usually affects both nostrils and the discharge is often serous.

Tumors, fungal infections, and chronic bacterial infections erode the nasal membranes producing a blood-tinged or bloody discharge. One or both nostrils may be involved. Cryptococcus is the most common fungal infection in the nose of cats. When there is blood in the discharge, the cat needs to see a veterinarian.

Nasal Infections

Bacterial infections become established when the lining of the nose has been injured by a foreign body or nasal trauma or by a prior viral respiratory disease. Nasal infections can cause sneezing, nasal discharge, noisy breathing, and mouth breathing. When nasal congestion interferes with the ability to smell, the cat loses his appetite and stops eating.

On occasion, infection spreads to the nasal cavity from the frontal sinus. This is often associated with an infected tooth root. Nasal infections can also be secondary to tumors in the nasal cavity. The chief sign of bacterial involvement is a nasal discharge that is mucoid, creamy yellow, or puslike. A bloody discharge indicates deep involvement with ulceration of the nasal membrane. The cat may also have a fever and may not be eating well.

The feline viral respiratory disease complex is the most common cause of nasal infection. Eighty to 90 percent of cats who recover from an infection become carriers of herpesvirus or calicivirus. During periods of stress, immunity breaks down and the disease is reactivated. Calicivirus may be shed almost continuously, without clinical signs, which means the cat can infect other cats. In some cases, the nasal infection is mild; in others there is a chronic, mucopurulent discharge from the eyes and nose. Chlamydia (also called Chlamydophila) infections rank second to viruses for causing feline nasal infections.

Treatment: The objectives are to restore breathing, treat and prevent infection, and keep the cat as comfortable as possible. Isolate the ill cat if possible to prevent the spread of illness to other cats in the home. Gently wipe the nostrils with a moist cotton ball or soft, clean cloth to remove crusts and secretions. Unscented baby wipes also work well. Gently rub a drop of baby oil, aloe, or baby lotion on the nose to keep nostrils from cracking and drying. Vaporizers loosen secretions and help to restore the integrity of the mucociliary blanket. Even closing your cat in the bathroom while you shower can help loosen up nasal secretions.

Encourage the cat to eat by feeding his favorite aromatic foods. You can also add the juice from a can of tuna to your cat's regular food. Gently warming food to make the smell more pronounced can also encourage eating. Cyproheptadine is an antihistamine that has been used as an appetite stimulant; your veterinarian can prescribe it if necessary. Adding the amino acid lysine as a supplement may help decrease herpesvirus in the respiratory tract.

A purulent discharge signifies a bacterial infection and indicates the need for an antibiotic. When the discharge persists despite treatment, your veterinarian will need to do a culture and sensitivity test to select the most appropriate antibiotic.

In long-standing cases suspect a fungus. A fungus may be identified by examining a nasal swab under a microscope. Your veterinarian will do this for long-term or recurrent cases. Fungal infections require special long-term medications.